Evaporation is an endothermic process. These types of reactions occur when the temperature of the system decreases and the surroundings gain energy. Endothermic reactions end up with an overall positive heat of reaction.
Endothermic reactions absorb energy from the reactions instead of releasing energy into their surroundings. Endothermic reactions have a positive heat of reaction and a positive enthalpy value. The enthalpy value is positive because endothermic reactions produce high enthalpy and high energy products. As a result the products of endothermic reactions have higher energy and enthalpy than the reactants. The other reaction type is exothermic. These reactions release energy into their surroundings and have an overall negative heat of reaction and change in enthalpy.